<template>
  <div id="home">
    <nav-bar class="home-nav">
      <div slot="center">购物街</div>
    </nav-bar>
    <tab-control
      class="tab-control"
      :titles="['流行','新款','精选']"
      @tabClick="tabClick" 
      ref="tabControl1" v-show="isTabFixed"/>
    <scroll class="content"
            ref="scroll"
            :probe-type="3"
            @scroll="contentScroll"
            :pull-up-load="true"
            @pullingUp="loadMore">
      <home-swiper :banners="banners" @swiperImageLoad="swiperImageLoad"/>
      <recommend-view :recommends="recommends"/>
      <feature-view/>
      <tab-control
      :titles="['流行','新款','精选']"
      @tabClick="tabClick" 
      ref="tabControl2"/>
      <goods-list :goods="showGoods"/>
    </scroll>
    <back-top @click.native="backClick" v-show="isShowBackTop"/>
  </div>
</template>

<script>
  import HomeSwiper from './childComps/HomeSwiper';
  import RecommendView from './childComps/RecommendView';
  import FeatureView from './childComps/FeatureView'

  import NavBar from 'components/common/navbar/NavBar'
  import TabControl from 'components/content/tabControl/TabControl'
  import GoodsList from 'components/content/goods/GoodsList'
  import Scroll from 'components/common/scroll/Scroll';

  import {getHomeMultidata, getHomeGoods} from 'network/home'
  import {itemListenerMixin, backTop} from 'common/mixin'

  export default {
    name: "Home",
    components: {
      NavBar,
      HomeSwiper,
      RecommendView,
      FeatureView,
      TabControl,
      GoodsList,
      Scroll,
    },
    mixins:[itemListenerMixin],
    data() {
      return {
        banners: [],
        recommends: [],
        goods: {
          'pop': {page: 0,list: []},
          'new': {page: 0,list: []},
          'sell': {page: 0,list: []},
        },
        currentType: 'pop',
        tabOffsetTop: 0,
        isTabFixed: false,
        saveY: 0
      }
    },
    mixins:[backTop],
    computed: {
      showGoods() {
        return this.goods[this.currentType].list;
      }
    },
    activated() {
      this.$refs.scroll.scrollTo(0, this.saveY, 0)
      this.$refs.scroll.refresh()
    },
    deactivated() {
      this.saveY = this.$refs.scroll.getScrollY()
    },
    created() {
      //1.请求多个数据
      this.getHomeMultidata()
      //2.请求商品数据
      this.getHomeGoods('pop')
      this.getHomeGoods('new')
      this.getHomeGoods('sell')  
    },
    methods: {
      swiperImageLoad() {
        //获取tabOffsetTop的offsetTop
        //所有的组件都有一个属性$el： 用于获取组件中的元素
        this.tabOffsetTop = this.$refs.tabControl2.$el.offsetTop
        // console.log(this.$refs.tabControl.$el.offsetTop);
      },
      loadMore() {
        this.getHomeGoods(this.currentType)
      },
      /**事件监听相关的方法 */
      tabClick(index) {
        switch (index) {
          case 0:
            this.currentType = 'pop';
            break;
          case 1:
            this.currentType = 'new';
            break;
          case 2:
            this.currentType = 'sell';
            break;
        }
        this.$refs.tabControl1.currentIndex = index
        this.$refs.tabControl2.currentIndex = index
      },
      
      contentScroll(position) {
        //1.判断BackTop是否显示
        this.isShowBackTop = -(position.y) > 560?true:false
        //2.决定tabControl是否吸顶（position: fixed）
        this.isTabFixed = -(position.y) > this.tabOffsetTop?true:false

      },
      /**网络请求相关的方法 */
      getHomeMultidata() {
        getHomeMultidata().then(res => {
          // console.log(res);
          this.banners = res.data.banner.list;
          this.recommends = res.data.recommend.list;
        })
      },
      getHomeGoods(type) {
        const page = this.goods[type].page + 1;
        getHomeGoods(type, page).then(res => {
          this.goods[type].list.push(...res.data.list);
          this.goods[type].page += 1;

          //完成下拉加载更多
          this.$refs.scroll.finishPullUp()
        })
      }
    },
  }

</script>

<style scoped>
#home {
    /*padding-top: 44px;*/
    height: 100vh;
    position: relative;
  }

  .home-nav {
    background-color: var(--color-tint);
    color: #fff;

    /*在使用浏览器原生滚动时, 为了让导航不跟随一起滚动*/
    /*position: fixed;*/
    /*left: 0;*/
    /*right: 0;*/
    /*top: 0;*/
    /*z-index: 9;*/
  }

  .content {
    overflow: hidden;

    position: absolute;
    top: 44px;
    bottom: 49px;
    left: 0;
    right: 0;
  }

  .tab-control {
    position: relative;
    z-index: 9;
  };
  
  /*.content {*/
    /*height: calc(100% - 93px);*/
    /*overflow: hidden;*/
    /*margin-top: 44px;*/
  /*}*/
</style>
